1. Field of the Invention
The invention, in its several embodiments, relates to capacitive antennas and particularly to capacitive antenna embodiments having a free space gap bounded by a first capacitive component and a second capacitive component in rotatable proximity to the first capacitive component and the invention, in its several embodiments, also relates to air vehicles so equipped.
2. State of the Art
The gain bandwidth product of a radiating element, such as an antenna for effecting radiofrequency communication, is proportional to volume. Efficient radiating structures that operate over a wide bandwidth require a minimum effective volume of 0.065 wavelength-cubed. This relates to an effective volume in the UHF band of around 2,700 cubic inches or a required volume, if completely contained in a missile or some other air vehicle, illustrated by a polyhedron having rectangular faces with dimensions of about 17.4 inches, 17.4 inches and 8.7 inches. A conventional antenna for air vehicles such as missiles is typically constrained to an electrically small antenna of approximately 4 inches in width by 8 inches in length by less than 1.5 inches in depth. Such volumetric constraints severely limit the bandwidth and efficiency of a conventional antenna.